docs: def _bbox_around_polycoords(coords):
      """
      bounding box
      """
      x_all = []
      y_all = []
  
      for first in coords[0]:
          x_all.append(first[1])
          y_all.append(first[0])
  
      return [min(x_all), min(y_all), max(x_all), max(y_all)]